Method of staining glass and glass staining composition



Patented Dec. 8, 1953 UNITED STATES PATENT OFFICE METHOD OF STAINING GLASS AND GLASS STAINING COMPOSITION Ormonde S. Levi, Toledo, hio, assignor to Verd- A-Ray Processing Company, Toledo, Ohio, a

corporation of Ohio No Drawing. Application May 13, 1953, Serial No. 354,895

15 Claims. 1

Same, filed April 3, 1950, now abandoned.

The art of staining to which the present invention is directed comprises the coloration of a glass surface, and is not to be confused with colored glass, wherein the molten glass batch is colored by the addition of suitable ingredients. In this connection, so-called stained glass windows are actually windows composed of small pieces of colored glass.

The art of staining glass with copper and/or silver compounds is several hundreds years old. Usually the copper or silver salt, or both, is mixed with a suitable ochre or dispersing agent, and enough water'added to provide a slurry of the desired viscosity. This slurry is then applied to the glass surface to be stained and the article is baked at a predetermined temperature to effect staining of the glass surface. The excess mud is then removed by washing and scrubbing. Copper salts have been used alone on borosilicate glass to provide a yellow stain and, upon reduction of the copper, a red stain. No stain is obtained by copper salt alone on soda-lime glass. Copper and silver salts have been. used in combination with one another to produce amber stains on soda-lime glass, but these stains are relatively light colored, being much too light for coloring incandescent light bulbs for therapeutic use. Also, the high temperatures required for effective staining using this stain composition, may

deform the thin bulb as well as metallize the staining ingredients, this latter effect greatly reducing the amount of light and heat transmitted through the bulb.

In spite of the'long period in which glassstains have been known and used, and in spite of con- There are definite advantages, however, to staining glassware rather than coloring the. en-

tire glass batch as is now the usual practice. In

the first place, partially finished glassware may be colored to order. This permits those manufacturers who provide finished articles to color their glassware independentlyof the operation of the manufacturer who produces the. glass.

Also, large colored articles, such as stained glass windows, may be produced in one sheet of glass rather than the multi-pieced leaded windows now made, and at a lower price.

Although glass enamel is the customary medium for applying labels and for decorating glassware, stains may be readily'applied and are much more permanent, lasting as long as the glass to which they are applied. This is especially important due to rigid State statutes requiring the use of strong alkalis in cleaning bottles, etc., these alkali cleaning agents rapidly deteriorating the glass enamel but having little or no eilect upon the stain. The use of stains in decorating glassware, however, has been restricted due to the limited number of colors obtainable and inability to control these colors.

An object of this invention, therefore, is to provide compositions and methods for staining glass in a, variety of colors, and thus produce new and improved stained glass articles.

Another object of this invention is to provide compositions and methods for staining glass uniformly and for producing a stain having an accurately predetermined and reproducible color.

Still another object of this invention is to provide compositions and methods for staining several types of glass, such as soda-lime, borosilicate, leadglasses, and the like, in a varietyof colors and in varying shades. p

A still further object of this invention is to provide compositions and methods for staining soda-lime glass at temperatures below the softening point of the glass as well as the metallizing point of the staincomposition, said stains being permanent, uniform and reproducible;

, A still further object ofthis invention is to provide stained glass articles in a variety of colors siderable research upon staining compositions,

the art of staining glass has advanced so little since early times that only a very limitednumis seldom practiced at the present time.

and. having accurately predetermined colors which are uniform throughout the stained area.

Still another object of this invention is to provide an amber lime glass and a method of making it that may be readily employed at a temperature low enough to avoid danger of deformation of thin glass, such as the walls of an incandescent lamp bulb, and still produce a deep amber stain includes the application thereto of a uniform oil dispersion which can be applied by brushing, spraying, screening or dipping, and havi h viscosity and spreading characteristics t a it can be applied and firedtoproduce glass surfaces stained in a desired pattern.

Other objects and advantages of this invention 1 will become apparent to those skilled in tl e art from the following detailed description rhe r'ecr.

THE INVENTION IN GENERAL It has been discoveredthat the combination of copper, silver and "zinc salts in the presence of inorganic chloride "compounds, in uniform'o'il dis- 'pfersion, produces an active material for's't'aining vvarious types of glass. Furthermore, the'color of the stain may be closely controlled'b'y'correctly proportioning the staining ingredients and by careful regulation of the baking'temperatures.

Staining compositions and manipulative steps illustrating 'the'method'of the'present invention 'areset forthi'n the'followingexamplesz Example 1."'A 'uniformd'ispersion was formed by grinding in a porcelain'lin'ed ball millprovide'd with porcelain balls the following composition:

granls QAg --.Q n Q7-rT -----,-r'1, "Aluminum chloride do 5.8 9 1 r .5 Alcohol "cc" 20 The resulting oil dispersion, "which'was of suit- "able'viscosity for spraying was applied to a g'lass bulb, and "the resulting coated bulbplaced in a 'mufil type furnace and fired to a temperature of about 1020f F., and allowed to 'cool. Residue remaining on the surface of the 'bulb was then 'washed off, and the bulb'was found to'have b'een "stained to a commercially acceptable green color. When' the procedure described in the preceding "paragraph was repeated exceptthatthenring temperature was lowered to iabout 975 F.,'-as1 amerciallyacceptableyellowstained bulb was produced. H

"Esc'dmplezr' lrocedures identical with that-fiescr'ibeddn'the' 'firstparag'raph of Example 1 were also carried-ouhbut using other inorganic chlor'idecompounds in "varying amounts inplace of the aluminum chloride. The chloride compounds 1 A. used, the amounts, the firing temperature, and the color of the resulting stains are presented in Table 1, below:

Table I j l i z ompov emsition ffg chlgnde Grams pera- Stain color No. pmm ture, F. 1 0

izi riuinblnb'ridc 13. 7 1, 020 yellow.

Cobaltous chloride. 8. 5 1, 020 green. Potassium chloride. 9.8 1, 020 reddish amber. Ammoniiimchlorld 7. 0 1, 020 Do. galciun hloride 7. 3 l, 020 green. Sodium c oride 7. 7 1, 020 reddish amber.

fEqittiii'pl iii- A procedure identical with that described in the first paragraph of Example 1 was I carriedout except that the following composition was employed in forming the uniform oil dispersion:

'Zinc chloridegrams 1 '14 Cup'rouschloride do '13 05 Silverchloride a do 1.2 Ochre ...dO

Oil- Y r M 50 Alcoho1- cc.... 40

The finished bulb was found to have been stained to a commercially acceptable green color. 159 No staining isefie'ctd if, for'purpo'ses of'compari'son, but not in accordance with the invention, 'the procedure described in paragraph 1 of EX- ample 11 is repeated using the following composi- 'tion to form the uniform oil dispersion:

v lthasbeen found that optimum results can be jachie'ved: according to the methodof the invention either when the" copper, zinc, andsilver's'alts far'eall' chlorides, and no other inorganicchloride jcorrrpou'nd is added, as in the procedure of Exple 3 abovefor when at least 'one of' the salts f oppen -silven'and zinc is'a sulfide, and the molecular ratio of sulfur to chlorine is from about 1.1015 to about 1:25. A series of stainingproceduresto demonstrate theadvantage' of a sulfur tio chlorine ratio-within the indicated range was "carried-'o'uL arfd theresults are reported in Exmr eai l werqmple grin 'rabie II, below, are presented :a'series 'offormulations demonstrating the dejs ability of suifurto chlorine ratios within the range indicateda'bove:

Table 'II o 'iii l on \i'th 1 thing when]? am 05 v l e ano empera- .ratio 0 on Na Zn GO ZnS CuCl AgzS Ochre co co tum, Sulphur m Stem-Color 7 Q chlorine 12. 0 0. 0 13. 0 1. 2 -80- 0 50. 0 40. 0 1, 020 1:30. 5 yellow. 11. 0 -1-. 0 a 13. 0 1. 2 80. 0 50. 0 40. 0 1,020 119. 73 Do. "'10. 0 2.0 "13. 0 1. 2 A80. 0 50. 0 40. 0 1,020 l: 5. 75 green.

. 8.0 4. 0 13. 0 1. 2 80. 0 50.0 40. 0 1, 020 1:3.19 Do. 6. 0 6. 0 13. 0 1. 2 0 50.0 40. 0 1, '020 1:2. 21 Do. 4. 0 8.0 13.0 1. 2 80.0 50. 0 40. O 1, 020 1:1. 68 Do. 1 0. 0 10, 0 13. 0 1. 2 .80. 0 50. 0 40. 0 1, 020 1:1. 36 Do. 0. 0 12, 0 13.0 1. 2 80. 0 50; 0 40. 0 1', 020 1:1. 14 Do. 0.0 14.0 13. 0 1.2 "-80.0 $50.0 40. 0 1,020 1:1 Do. 0. O 16. 0 13. 0 1. 2 80.0 50. 0 .40. 0 1, 1:0. 862 Do. 0. 0 18. 0 13. 0 1. 2 80'. 0 "50. 0 40'. 0 1, 020 1:0. 772 reddish amber. 0.0 20.0 13.0 1. 2 80. 0 50. 0 40. 0 1, 020 1:0.-695 'D0.

is; I

sFlrlng Temperature "these metals constitute the active staining por- .Most desirably, at leasttwo. of the salts of cop.-

per, silver and zinc'are sulfides,and the molecular ratio of sulfur to chlorine is from about 1:1

to about :1. i

. Example 5..A procedure identical with that ,5 described in the first paragraph of Example 1 .was carried out, except that the copper salt constituted also the inorganic chloride compound. The formulation employed was as follows:

An excellent green stain was produced on the glass surface.

Example 6.A series of stain compositions was produced, and each composition was used to stain glass further to illustrate the invention. The

formulations of the stain compositions and the results are presented in Table III below:

TABLE HI 50 F l, 020 Stain Color 1 Yellow. 2 Green.

, 8 Reddish amber.

Although the salts of copper, silver and zinc are generally applicable, salts wherein the metal cation predominates, or approximates per cent by weight of the salt, are much to be preferred over salts having extremely large anions. The reason for this is due to the dilution effect of the large anions upon the concentration of the metal component or ion which effects the staining of the glass. Thus, the cuprous compounds are preferred rather than the cupric because there is a higher percentage of copper in the former than in the latter. Salts of the oxygenfree strong mineral acids are particularly satisfactory, since the anion portion of the salt is .The use of chloride salts of copper, silver and zinc, or of one of them, is advantageous because, in such case, the copper, silverand zinc salts provide, also, the inorganic chloride compound.

, The copper, silver and zinc in the salts of tions o f their respective salts in staining according to the invention. j Therefore, the relative ages beingbased upon the total weight of the 7 0 three 5 metal ions, calculated as metals.

Staining compositions can be obtained by combining Cu, Ag and Zn salts in widely varying ;prop ortions., There are no sharp limits delineat- ;lpe;, .=omnp i qnswh ch l stain s a s ndcemw reasons, from about 2.8 per cent toabout 1 positions which will not. It is essential, however, that all three metal cations be present, since the absence of any one is fatal to the improved staining characteristics attained by the combination of the three. .While the .minimum amount, calculatedasabove described, of each of the three metal ions. required for staining according. to the method of the invention will vary slightly depending upon the other components of the staining composition, at least about 0.875 per cent of Ag, at least about 1.8 per cent of Zn, and at least about 15 per cent of Cu are required to produce an active staining material having the improved staining characteristics hereindescribed. The terms per cen and parts are used herein and in the appended claims to refer to per cent and parts by weight, unless otherwise indicated. For preferred results, the lower limit of Ag should be at least about 2.5 per cent; the lower limit of Zn should be at least about 20 per cent; and thelower limit of Cushould be at least about 40 per cent. Best commercial stains are produced when the Ag content is from about 2.5 per cent toabout 10 per cent. The particle size of these staining ingredientsis important, since larger particles do not react as quickly or as thoroughly and uniformly as do the smaller particles. For most effective results it is usually preferred that the particle size of the active staining ingredients in the uniform oil dispersion is all minus 300 mesh, U. S. Sieve Series, although satisfactory results can be achieved when the particle size of the material is all minus 100 mesh, preferably minus 150 mesh.

The maximum amounts of each of these metal ions permissible in staining compositions is established, in part, by the minimals of the other two, but over 21 per cent of Ag has no apparent beneficial effect upon the staining properties of the composition. With the usual grade of zinc sals, such as ZnS, dependable stains are difficult' toobtain when over. per cent of Zn is present, but the useof extremely finely divided ZnS, for example, permits as high as per cent of Znto be employed. Copper in amounts as high as about percent may be employed, but 85 per cent of Cu is preferred as an upper limit. e r

In addition to the copper, silver and zinc ions, it is necessary that at least a certain amount of an inorganic chloride compound be present. The

presence of as little as 1.4 per cent of chlorine, derived from one or more of the salts of copper, silver and zinc, or derived from another inorganic chloride compound, and based upon the total amount of copper, silver and zinc, calculated as metals, is sufficient to cause the appear ance of some green staining; When at least about 2.8 per cent of chlorine, calculated as indicated, is present, a good green stain can be obtained. Additional amounts ofchlorine do not ..produce any. material change in the staining properties of the composition other than a slight darkening, until the amount. thereof exceeds about per cent, calculated as indicated. Chlorine above this percentage may causeetch ing of the glass and deterioration of the staining color and is, thereforeundesirable. Accordingly, any amount of' chlorine from about 1.4 per cent to about 115 per cent, calculated as indicated, is satisfactory. Ordinarily, for practical per cent 9? .1Q1 p fiiqlldr.

wea es able. The composition of :the ochre usedin examples hereinbefore set forth is as follows:

Ferric oxide 52 5 silica is 26.37 Alumina p I 11:05 Moi tur huh-h sh? 081 Less onignition l, 9.125

Elihe exact eompo i ion of th ochre i a ma er of choice, but a particular ochre should he selected and standardized .if accurate .l'eproriuction :of stain colors is to be achieved, since the ochre composition :does afieot the color of th stain to a certain extent. The .amount of dispersing agent will vary :with the composition of the active staining ingredients, but must be 10011- trolled :within :certain limits, since an extremely Wide range may even vary the color of the stain, due to the dilution effect. Other dispersing agents may :be used, but ochre is preferred because of its low costand availability.

Oil is used in amounts suificient to form the r staining ,composition into a .slip having the desired consistency. The consistency or viscosity desired of a staining slip will vary with the "intended use. Whena'flat'surface is to Joe stained, a relatively thin or low viscosity slip may :be employed satisfactorily. When .a curved surface, such as a lamp bulb, :is to be stained, a m r viscous .slip must be provided in orderwto be retained in a uniform layer-upon the surface. The amount of oil employed will also vary considerably With-the particular ingredients of the stain. For example, :much less oil is ;required to achieve a given viscosity for a stain-in which the dispersing agent or ochre has been omitted than in one which contains a large amount of ochre. In addition, if the stain composition is to be iused. .for decorating glassware, as .by applying it in a desired pattern to a glass surface, for example, by a silk screening technique, the viscosity of the staining composition must be controlled .within relatively vnarrow limits .so that application by spraying is possible, .but .thestain slurry, after application, does not run or spread from the pattern in which it has been applied. Since the amount of oil required varies With both .the end use and the stain composition, no practical ilimitations'therefor can be set, but any one skilled in the art may readily determine by routine experiment that proportion of oil which is most desirable under any given circumstances. In general, theidentity'of the oil'used forforming the uniform dispersion for staining ingredients is not material, since'th e 'oil is used only as a carrier for the staining ingredients and does not enter into the actual staining reaction. However, unless particular viscosity characteristics are-desired of thesta'i-ning com-position it ispreferred-to use water as the carrier for the active staining ingredients as disclosed and claimed in my co-pending application "Serial 321,275,

now abandoned; Accordingly, when an .oil dis -persion is employed, this is usually in order to achieve a particularldesired result with the staining composition, which result is frequently .a deooration of .a glass surface by staining techniques, as described above. Therefore, the use of conventional screening oils for forming dispersions for'stai-ning glass according to the invention is usually preferred, even though various other 'oils and even lower petroleum fractions such as gasoline, naphtha and kerosene alcohols and other volatile solvents can also be employed. In any event, the oil that is used should be one that is volatilized at a temperature below about 800 'F., approximately the minimum temperature at which staining can be effected according "to the invention, as hereinafter described.

METHOD OF MAKING AND APPLYlN-GTHE STAIN COMPOSITION The various ingredients of the stain composition may be combined by a number of different procedures, none .of which appears materially to affect the staining characteristics of the resulting composition. One procedure which has been found to be highly satisfactory for preparing the staining composition involves grinding the various components of the stain in a ball mill containing porcelain balls. The copper, silver and zinc salts may be added to the ball mill, followed by approximately half the total amount of oil to be added to the composition. The stain in.- gredients are then ground, preferably until they will pass th ough a 200 mesh screen, U. .S. Sieve Series, at which time the remaining portion of the oil is added to make a slurry of the desired consistency. The particle size of the active staining ingredients affects the staining properties of the composition as above noted.

The staining composition is applied to thesurface of the article to be stained by dipping, spraying, brushing, screening, or the like. The .dipping procedure is fast and adaptable to automatic assembly line procedure, but, as above noted, oil dispersions are preferably used when their particular characteristics are desired, for example, because silk screening is to be employed. Control of the viscosity of the slurry, in any event, is required in order to obtain a coating of the stain composition of optimum thickness :by the particular technique of application being employ ed. When the stain coating or mud is too thick, cracks form .during'the baking procedure which ultimately show up in the finished article as unstained lines. If the slurry is too thin, the tai m y no be c ntinuous or m y b to l h b cause .of l w ncentrati n f t e a ve stainin in redi nt Routine xpe im t Wi le te'bhen the satisfactory viscosity that is best for any p rticular op ation.

In the baking operation, fairly close control of the temperatureof the blast must be maintained to obtain desired, predetermined "color. The "temperature employed will be determined in'part by the melting or softening point of the glass being stamedr-but temperatures in excess of 1100" F. destroy the staining composition'by 'metallizingqthe copper, silver and zinc salts. "Since there-is considerable'lag in temperature rise between theair in an oven and' the glass body, temperature should be taken directlyfrom the glass surface that is being stained. 1 Indirect heating or heating by conduction fis preferred -to direct heatingbyradiation, since more uniform heating of all sides of the article =to-'-be stained rnaybe obtained.v in baking the mud coated about 900 F. If the glass article is relatively thin so that no strains will develop, it may then be immediately removed from the oven and allowedto cool in the air. For thicker articles, such as heavy bottles or flatware, cooling should be gradual. The mud is then removed by washing and brushing, and the finished stained article is obtained. Throughout this specification staining temperatures given are the temperatures to which the glass surface has been heated, and the above-described staining procedure is employed unless otherwise stated.

For best results in staining aged glass or glass which contains decolorants, such as selenium and antimony, a prebaking process is quite advantageous. The glass surface to be stained is heated to a temperature slightlyin excess of that which is to be used in the staining operation and then allowed to cool. The heat treated surface may then be washed andsubsequently stained as above described. .Much deeper stains result when this prebaking step is employed 'on the aged glass or glass containing decolorantsthan when the glass is directly stained without this preliminary step. v V

' ooLoR on sT'AIN's Stain compositionscomprising the'present invention have the remarkable property of producing a variety of stains upon many different types of glass surfaces; Also, these stain compositions' produce colors never before obtained in glass. stains. Numerous. factors are interrelated in determining the color of the stain produced.

The'respective amounts of the four active staining ingredients present," and particularly the amount of silver, plays a major role incolor determination. The baking isanother factor which may be employed to control the color of the stain. As above indicated, the amount and type of ochre, the type of glass, the presence of sulfides, and the particle size of the active staining ingredients also affect the color of the stain to a lesser degree, and so must be standardized to obtain careful color control and to reproduce a given color.

An amber color stain is obtained when the baking temperature ranges from 800 F. to 925 F., regardless of the particular amounts ofthe active staining ingredients. When the Ag ion is present in amounts over 21% (of Cu, Zn, Ag total), an amber is obtained at any baking temperature between 800 F. and 1100? F., the upper limit established by the decomposition point of the staining ingredients. With staining compositions con taining less than 21% Ag ion, a red or green stain is obtained at baking temperatures between 925 and 1100 F., depending upon the composition of the stain. Red stains may be obtained even with the lower amount of Ag ion, which usually produces a green stain, by carefully maintaining the aceaos'c duce a stained glass surface.

.red. stain. Over 2'l-per cent of silver an amber stainiis'obtained even at baking temperatures at 1000" F., and little change is obtained by increas ingthesilver above this percentage.

been established thateach element of the combination of active staining ingredients is required,

and that aninorgan'ic chloride compound .is also necessary. p

STAINING "DIFFERENT GLASSES Stain compositions of the present invention are useful, not only in' the staining of soda-lime glass, but other types as well, including lead glass, borosilicate' glass, etc. Different colors maybe obtained on different typesof glasses with the same staining composition.

Having'described the invention, I'claim:

A'me'thod of staining glass surfaces which comprises forfning'a finely'divided, uniform oil dispersion containingcopper, silver and zinc salts and an inorganic chloride compound in amounts sufficient to stain glass, and in proportions such that, based 'on'the'total amountof copper, silver and zinc present, calculated as metals, copper constitutes from about 15 per c'ent'to about 90 per cent, silver at least about'0.875 percent, and zinc" at least'about 1.7"per cent, and chlorine, based ori the total amount of copper, silver, and zincpresentycalculated as metals, constitutes at least 1.4 percent but not more than about 115per cent; coating a glass surface with said dispersion, and heating the coated glass surface to a'temperature from about 800 F. to about 1100F; to pro- 2. 'A method of' staining glass'surfaces which comprises forming a finely divided, uniform oil dispersion containing copper, silver and zinc salts and analkali metal'chlori'de in amounts'sufiicient to stain glass, and inp'roportions such that, based on the-total amount of copper, silver and zinc present, calculated as metals, copper constitutes from about 15 per cent to about 90 per cent, silver at least about 0.875 per cent, and zinc at least baking temperature just below 1000 F., but such 10 per cent of silver, and above 10 per centof silver bu und r 21 per cent of silver results in a about 1.7 per cent, andchlcrine, based on the total amount of-copper; silver, and zinc present, calculated as metalsgconstitutes at least 1.4 per cent butfnot more than about 115 per cent, coating a glass surface with saiddispersion, and heating the coated glass surface to a temperature from about 800F. to about 1100. F. to produce a stained glass'surface.

3: A'method of'staining glass surfaces which comprises forming a finely divided, uniform oil dispersion containing copper, silver and zinc salts and'an alkaline earthchloride in amounts sufficient to'stainglass, and in proportions such that, based on the total amount of copper, silver and zinc present, calculated as metals, copper constitutes from about" 15 per cent to about per cent, silver at leastabout 0.875 per cent, and zinc at least about'lfl per cent,and chlorine,-based on the total amount ofcopper, silver, and zinc present,rcalculated-as metals, constitutes-at least 1.4 per cent but not more than about per cent,

While this transition from green to red to amber coating a glass surface with said dispersion, and heating the coated glass, surface to a temperature -from about 800 F. to about 1 100'F. to produce a stained glass surface.

4,. A method of staining glass surfaces which .total amount of copper, silver and zinc present,

calculated as metals, constitutes at least 1.4 per cent but not more than about 115 per cent, coating a glass surface with said dispersion, and heating the coated glass surface to a temperature from about 800 F. to about 1100 F. to produce a stained glass surface.

5. A method of staining glass surfaces which comprises forming a finely divided, uniform oil dispersion containing coppensilver and zinc salts and ammonium chloride in amounts sufficient to stain glass, and in proportions such that, based on the total amount of copper, silver and zinc present, calculated as metals, copper constitutes from about 15 per cent to about 90 per cent, silver at least about 0.875 per cent, and zinc at least about 1,7 per cent, and chlorine, based on the total amount of copper, silver, and zinc present, calculated as metals, constitutes at least 1.4 per cent but not more than about 115 per cent, coating a glass surface with said dispersion, and heating the coated glass surface to a temperature from about 800 F. to about 1100" F. to produce a stained glass surface.

6. A method of staining glass surfaces which comprises forming a finely divided, uniform oil dispersion containing copper, silver and zinc salts, at least two of which salts are sulfides, and an inorganic chloride .compound in amounts suffi cientto stain glass, andin proportions such that, based on the total amount of copper, silver and zinc present, calculated as metals, copper constitutes from about '15 per cent to about 90 per cent, silver at least about 0.875 per cent, and zinc at least about 1.7- per cent, and in proportions such that the molecular ratio of sulphur to chlorine is from 110.5 to 1:25, coating a glass surface with said' dispersion, and" heating the coated gle ss surface to a temperature from about 800'- F. to about 1100 'F. to produce a stained glass-surface.

7, A method of staining glass surfaces which comprises forming a finely divided, uniform oil dispersion containing copper, silver and'zinc-salts, at least two of which salts are sulfides, and an alkali-metal chloride in amounts sufficient to stain glass, and in proportionssuch that, based on the total amount of copper, silver and zinc present, calculated as metals, copper constitutes from about 15 per cent-to'about 90 per cent, silver at least about 0.875 per cent, and zinc at least about 1.7 per cent, and in proportions such that the molecular ratio of sulphur to chlorine is from 1:05 to 1:25, coating a glass surf-ace with said dispersion, and heating the coatedv glass surface to a temperature from about 800 F. to about 1100- F. to produce a stained glass surface.

'8. A method of staining glass surfaces which comprises forming a finely divided, uniform oil dispersion containing copper, silver-and "zinc salts, atileast two of which salts are sulfides, and an comprises forming a finely divided, uniform oil' alkaline earth chloride in amounts sumcient. to stain glass, and in proportions such that, based on the total amount of :copper, silver and zinc present, calculated as metals, copper constitutes from about 15 per cent to about 90 per cent, silver at least about 0.875 per cent, and zinc at least about 1.7 per cent, and in proportions such that the molecular ratio of sulphur to chlorine is from 1:0.5 to 1:25, coating a glass surface with said dispersion, and heating the coated glass surface to a temperature from about 300 F. to about 1100 F. to produce a stained glass surface.

9, A method of staining glass surfaces which comprises forming a finely divided, uniform oil dispersion containing copper, silver and zinc salts, at least two of which salts are sulfides, and aluminum chloride in amounts sufficient to stain glass, and in proportions such that, based on the total amount of copper, silver and zinc present, calculated as metals, copper constitutes from about 15 per cent to about 90 per cent, silver at least about 0,875 per cent, and zinc at least. about 13 per cent, and. in proportions such that the molecular ratio of sulphur to chlorine is from 120.5 to 1:25, coating a glass surface with said dispersion, and heating the coated glass surface to a temperature from about 800 F. to about 1100 F. to produce a stained glass surface.

10. A method of staining glass surfaces which comprises forming a finely divided, uniform oil dispersion containing copper, silver and zinc salts, at least two of which salts are sulfides, and an ammonium chloride in amounts sufficient to stain glass, and in proportions such that, based on the total amount of copper, silver and zinc present, calculated as metals, copper constitutes from about 15 per cent to about 90 per cent, silver at least about 0.875 per cent, and zinc at least about 1.7 per cent, and in proportions such that the molecular ratio of sulphur to chlorine is from 1:05 to 1:25, coating a glass surface with said dispersion, and heating the coated glass surface to a temperature from about 800 F. to about 1100* F. to produce a stained glass surface.

11. A method of staining glass surfaces which comprises forming a finely divided, uniform oil dispersion containing copper, silver and zinc salts and calcium chloride in amounts suficient to stain glass, and in proportions such that, based upon the total amount of copper, silver and zinc present, calculated as metals, copper constiat least about 1.7 per cent, and chlorine, basedtutes from about 15 per cent to about Super cent, silver at least about 0.875 per cent, and zinc at least about 1.7 per cent, and chlorine, based on the total amount of copper, silver, and zinc pres.- ent, calculated as metals, constitutes at least 1.4 per cent but not more than about 115 per cent, coating a glass surface with said dispersion, and heating the coated glass surface to a temperature from about 800 F. to about 1100 F. to produce a stained glass surface.

12. A method of staining glass surfaces which comprises forming a finely divided, uniform oil dispersion containing copper, silver and zinc salts and potassium chloride in amounts suflicient to stain glass, and in proportions such that, based upon the total amount of copper, silver and zinc present, calculated as metals, copper constitutes from about 15 per cent to about per cent, silver at-least about'0.87 5 per cent, and zinc on the total amount of copper, silver, and zinc present, calculated as metals, constitutes at least 1.4 percent but not more than about per cent, coating aglasssurface with said dispersion, and heating the coated glass surface to a temperature from about 800 F. to about 1100" F. to produce a stained glass surface.

13. A method of staining glass surfaces which comprises forming a finely divided, uniform oil dispersion containing copper, silver and zinc chlorides in amounts sufficient to stain glass, and in proportions such that, based on the total amount of copper, silver and zinc present, calculated as metals, copper constitutes from about 15 per cent to about 90 per cent, silver at least about 0.875 per cent, and zinc at least about 1.7 per cent, coating a glass surface with said dispersion, and heating the coated glass surface to a temperature from about 800 F. to about 1100 F. to produce a stained glass surface.

14. A composition of matter for staining glass comprising a finely divided, uniform oil dispersion containing copper, silver and zinc salts and an inorganic chloride compound in amounts sufiicient to stain glass, and in proportions such that, based on the total amount of copper, silver and zinc present, calculated as metals, copper constitutes from about 15 per cent to about 90 14 per cent, silver at least about 0.875 per cent, and zinc at least about 1.7 per cent, and chlorine, based on the total amount of copper, silver and zinc present, calculated as metals, constitutes at least 1.4 per cent but not more than about 115 per cent.

15. A composition of matter for staining glass comprising a finely divided, unform oil dispersion containing copper, silver and zinc salts and an inorganic chloride compound in amounts sufficient to stain glass, and in proportions such 'that, based upon the total amount of copper,

silver and zinc present, calculated as metals, copper constitutes from about 40 per cent to about per cent, silver from about 0.875 per cent to about 21 per cent, and zinc at least about 1.7 per cent, and chlorine, based on the total amount of copper, silver and zinc present, calculated as metals, constitutes at least 2.8 per cent but not 20 more than about per cent.

ORMONDE S. LEVI.

No references cited. 

1. A METHOD OF STAINING GLASS SURFACE WHICH COMPRISES FORMING A FINELY DIVIDED, UNIFORM OIL DISPERSION CONTAINING COPPER, SILVER AND ZINC SALTS AND AN INORGANIC CHLORIDE COMPOUND IN AMOUNTS SUFFICIENT TO STAIN GLASS, AND IN PROPORTIONS SUCH THAT, BASED ON THE TOTAL AMOUNT OF COPPER, SILVER AND ZINC PRESENT, CALCULATED AS METALS, COPPER CONSTITUTES FROM ABOUT 15 PER CENT TO ABOUT 90 PER CENT SILVER AT LEAST ABOUT 0.875 PER CENT, AND ZINC AT LEAST ABOUT 1.7 PER CENT, AND CHLORINE, BASED ON THE TOTAL AMOUNT OF COPPER, SILVER, AND ZINC PRESENT, CALCULATED AS METALS, CONSTITUTES AT LEAST 1.4 PER CENT BUT NOT MORE THAN ABOUT 115 PER CENT, COATING A GLASS SURFACE WITH SAID DISPERSION, AND HEATING THE COATED GLASS SURFACE TO A TEMPERATURE FROM ABOUT 800* F. TO ABOUT 1100* F. TO PRODUCE A STAINED GLASS SURFACE. 